I. Product Definition and Core Parameters

Essential Attributes

This is a carbon motor brush with dimensions of 6.3×12.5×18 mm, designed as a wear-and-tear replacement part specifically for electric power tools. It is used for conducting electric current within the motor.

Key Dimensions

• Length: 18 mm

• Width: 12.5 mm

• Thickness: 6.3 mm
  These dimensions are tailored to fit the carbon brush slots of small and medium-sized power tool motors.

II. Application Scenarios and Typical Tools

Scope of Application

Suitable for various electric power tools driven by DC or AC commutator motors, including:

• Drills

• Angle grinders

• Circular saws

• Rotary hammers

• Polishers

Compatibility Logic

This size is a universal specification commonly found in small and medium-sized tool models from brands such as Bosch, DeWALT, Makita, etc. (e.g., Bosch TSB5500 drill, Makita 9557NB angle grinder). Compatibility must be verified against the actual dimensions of the motor's carbon brush slot.

III. Working Principle and Wear Mechanism

Current Conduction Principle

• The carbon brush maintains sliding contact with the motor commutator through spring pressure, transmitting electrical current from the power source to the rotor windings to drive motor rotation.

• The graphite-based material combines electrical conductivity with wear resistance to ensure stable contact under high-speed operation (e.g., angle grinders at 10,000 RPM).

Wear Replacement Threshold

During normal use, the carbon brush gradually wears down due to friction. Replace it immediately when:

• The remaining length is less than 1/3 of the original length.

• Severe sparking occurs.

• The motor exhibits reduced power.
  Failure to replace may damage the commutator.

IV. Installation and Maintenance Key Points

Installation Steps

1. Power off the tool and remove the rear cover. Extract the old carbon brush and spring.

2. Clean the commutator surface with alcohol to remove carbon powder and ensure no oil contamination.

3. The new carbon brush must fit the commutator arc (use sandpaper to adjust the curvature if necessary). The spring should maintain a pressure of 1.5–2 kg.

Maintenance Value

Regularly inspect the carbon brush wear (recommended every 50 hours of use) to prevent motor overheating or jamming due to poor contact.

V. Technical Differences from Other Carbon Brushes

VI. Purchase and Replacement Recommendations

Specification Verification

In addition to dimensions, confirm:

• Current carrying capacity (typically 10–15A).

• Compatible motor voltage (12V/24V/220V).

Professional Tips

If the tool exhibits abnormal sparking or reduced speed, the carbon brush or spring may be worn. Replace both components as a set for optimal pressure parameter matching.

Conclusion

This carbon brush is a core consumable component for power tool motors. Its standardized dimensions and material design meet the current conduction requirements under high-speed, heavy-load conditions. Proper replacement requires attention to both dimensional compatibility and installation techniques to ensure stable restoration of tool performance.